Commit Graph

398 Commits

Author SHA1 Message Date
Eli Friedman
c6b018b737 PR9346: Prevent SimplifyDemandedBits from incorrectly introducing
INT_MIN % -1.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127306 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09 01:28:35 +00:00
Devang Patel
5aa3fa6d82 llvm.dbg.declare intrinsic does not use any llvm::Values. It's magic!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127282 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-08 22:12:11 +00:00
Nick Lewycky
dcf77575d2 Reorder comments to put them the right way around.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127220 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-08 06:29:47 +00:00
Nick Lewycky
c14bc77315 Add more analysis of the sign bit of an srem instruction. If the LHS is negative
then the result could go either way. If it's provably positive then so is the
srem. Fixes PR9343 #7!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127146 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-07 01:50:10 +00:00
Nick Lewycky
d01f50f42c ConstantInt has some getters which return ConstantInt's or ConstantVector's of
the value splatted into every element. Extend this to getTrue and getFalse which
by providing new overloads that take Types that are either i1 or <N x i1>. Use
it in InstCombine to add vector support to some code, fixing PR8469!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127116 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-06 03:36:19 +00:00
Benjamin Kramer
103391d639 InstCombine: We know the number of items initially added to the worklist map, reserve space early to avoid rehashing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127089 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05 16:43:46 +00:00
Nick Lewycky
58bfcdbcf6 Thread comparisons over udiv/sdiv/ashr/lshr exact and lshr nuw/nsw whenever
possible. This goes into instcombine and instsimplify because instsimplify
doesn't need to check hasOneUse since it returns (almost exclusively) constants.

This fixes PR9343 #4 #5 and #8!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127064 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05 05:19:11 +00:00
Nick Lewycky
9feda1730c Try once again to optimize "icmp (srem X, Y), Y" by turning the comparison into
true/false or "icmp slt/sge Y, 0".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127063 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05 04:28:48 +00:00
Anders Carlsson
d70be0b2c1 Make InstCombiner::FoldAndOfICmps create a ConstantRange that's the
intersection of the LHS and RHS ConstantRanges and return "false" when
the range is empty.

This simplifies some code and catches some extra cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126744 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01 15:05:01 +00:00
Nick Lewycky
3dc7e49c70 srem doesn't actually have the same resulting sign as its numerator, you could
also have a zero when numerator = denominator. Reverts parts of r126635 and
r126637.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126644 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-28 09:17:39 +00:00
Nick Lewycky
b042f8e969 Teach InstCombine to fold "(shr exact X, Y) == 0" --> X == 0, fixing #1 from
PR9343.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126643 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-28 08:31:40 +00:00
Nick Lewycky
d8d1584c13 The sign of an srem instruction is the sign of its dividend (the first
argument), regardless of the divisor. Teach instcombine about this and fix
test7 in PR9343!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126635 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-28 06:20:05 +00:00
Chris Lattner
091b1e3c74 change instcombine to not turn a call to non-varargs bitcast of
function prototype into a call to a varargs prototype.  We do
allow the xform if we have a definition, but otherwise we don't
want to risk that we're changing the abi in a subtle way.  On
X86-64, for example, varargs require passing stuff in %al.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126363 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-24 05:10:56 +00:00
Benjamin Kramer
38f7f66fcc Move "A | ~(A & ?) -> -1" from InstCombine to InstructionSimplify.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126082 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-20 15:20:01 +00:00
Benjamin Kramer
91e37ef278 InstCombine: Add a bunch of combines of the form x | (y ^ z).
We usually catch this kind of optimization through InstSimplify's distributive
magic, but or doesn't distribute over xor in general.

"A | ~(A | B) -> A | ~B" hits 24 times on gcc.c.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126081 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-20 13:23:43 +00:00
Eli Friedman
1347623aaf PR9218: SimplifyDemandedVectorElts can return a non-null value that is not
the instruction passed in.  Make sure to account for this correctly, instead
of looping infinitely.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126058 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-19 22:42:40 +00:00
Duncan Sands
39a7de72c8 Add some transforms of the kind X-Y>X -> 0>Y which are valid when there is no
overflow.  These subsume some existing equality transforms, so zap those.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125843 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-18 16:25:37 +00:00
Chris Lattner
c8cb8ef9c2 have instcombine preserve nsw/nuw/exact when sinking
common operations through a phi. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125790 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 23:01:49 +00:00
Chris Lattner
1521e91fc4 fix typo
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125787 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 22:32:54 +00:00
Chris Lattner
4bd8217af3 fix instcombine merging GEPs through a PHI to only make the
result inbounds if all of the inputs are inbounds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125785 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 22:21:26 +00:00
Chris Lattner
bd9f6bf5cd add is always integer, thanks to Frits for noticing this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125774 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 20:55:29 +00:00
Duncan Sands
a77243300b Transform "A + B >= A + C" into "B >= C" if the adds do not wrap. Likewise for some
variations (some of these were already present so I unified the code).  Spotted by my
auto-simplifier as occurring a lot.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125734 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 07:46:37 +00:00
Chris Lattner
41429e3f1e preserve NUW/NSW when transforming add x,x
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125711 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 02:23:02 +00:00
Duncan Sands
ab4c366274 Spelling fix: consequtive -> consecutive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125563 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 09:23:02 +00:00
Nadav Rotem
d9e087bbc3 Fix 9216 - Endless loop in InstCombine pass.
The pattern "A&(A^B) -> A & ~B" recreated itself because ~B is
actually a xor -1.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125557 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 07:13:48 +00:00
Devang Patel
e7394ea9c6 Do not forget DebugLoc!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125547 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 02:02:30 +00:00
Chris Lattner
da1d660aa2 tidy up a bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125546 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 01:56:08 +00:00
Chris Lattner
2ca5c8644e convert ConstantVector::get to use ArrayRef.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125537 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 00:14:00 +00:00
Chris Lattner
7583190422 revert my ConstantVector patch, it seems to have made the llvm-gcc
builders unhappy.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125504 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-14 18:15:46 +00:00
Chris Lattner
283c8caccd Switch ConstantVector::get to use ArrayRef instead of a pointer+size
idiom.  Change various clients to simplify their code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125487 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-14 07:55:32 +00:00
Chris Lattner
e5116f840e remove a now-unneccesary cast.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125464 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 18:30:09 +00:00
Chris Lattner
bb75d337c4 implement instcombine folding for things like (x >> c) < 42.
We were previously simplifying divisions, but not right shifts!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125454 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 08:07:21 +00:00
Chris Lattner
74542aa500 refactor some code out into a helper method.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125451 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 07:43:07 +00:00
Benjamin Kramer
b6c8cb4422 Also fold (A+B) == A -> B == 0 when the add is commuted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125411 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-11 21:46:48 +00:00
Chris Lattner
6aa68a7647 When lowering an inbounds gep, the intermediate adds can have
unsigned overflow (e.g. due to a negative array index), but
the scales on array size multiplications are known to not
sign wrap.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125409 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-11 21:37:43 +00:00
Chris Lattner
6cdf2ea98e implement the first part of PR8882: when lowering an inbounds
gep to explicit addressing, we know that none of the intermediate
computation overflows.

This could use review: it seems that the shifts certainly wouldn't
overflow, but could the intermediate adds overflow if there is a 
negative index?

Previously the testcase would instcombine to:

define i1 @test(i64 %i) {
  %p1.idx.mask = and i64 %i, 4611686018427387903
  %cmp = icmp eq i64 %p1.idx.mask, 1000
  ret i1 %cmp
}

now we get:

define i1 @test(i64 %i) {
  %cmp = icmp eq i64 %i, 1000
  ret i1 %cmp
}



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125271 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 07:11:16 +00:00
Chris Lattner
7a6aa1a391 Enhance a bunch of transformations in instcombine to start generating
exact/nsw/nuw shifts and have instcombine infer them when it can prove
that the relevant properties are true for a given shift without them.

Also, a variety of refactoring to use the new patternmatch logic thrown
in for good luck.  I believe that this takes care of a bunch of related
code quality issues attached to PR8862.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125267 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:36:31 +00:00
Chris Lattner
b20c0b5092 Enhance the "compare with shift" and "compare with div"
optimizations to be much more aggressive in the face of
exact/nsw/nuw div and shifts.  For example, these (which
are the same except the first is 'exact' sdiv:

define i1 @sdiv_icmp4_exact(i64 %X) nounwind {
  %A = sdiv exact i64 %X, -5   ; X/-5 == 0 --> x == 0
  %B = icmp eq i64 %A, 0
  ret i1 %B
}

define i1 @sdiv_icmp4(i64 %X) nounwind {
  %A = sdiv i64 %X, -5   ; X/-5 == 0 --> x == 0
  %B = icmp eq i64 %A, 0
  ret i1 %B
}

compile down to:

define i1 @sdiv_icmp4_exact(i64 %X) nounwind {
  %1 = icmp eq i64 %X, 0
  ret i1 %1
}

define i1 @sdiv_icmp4(i64 %X) nounwind {
  %X.off = add i64 %X, 4
  %1 = icmp ult i64 %X.off, 9
  ret i1 %1
}

This happens when you do something like:
  (ptr1-ptr2) == 42

where the pointers are pointers to non-unit types.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125266 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:23:05 +00:00
Chris Lattner
44cc997d42 more cleanups, notably bitcast isn't used for "signed to unsigned type
conversions". :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125265 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:17:27 +00:00
Chris Lattner
b9b9044600 A bunch of cleanups and simplifications using the new PatternMatch predicates
and generally tidying things up.  Only very trivial functionality changes
like now doing (-1 - A) -> (~A) for vectors too.

 InstCombineAddSub.cpp |  296 +++++++++++++++++++++-----------------------------
 1 file changed, 126 insertions(+), 170 deletions(-)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125264 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:14:58 +00:00
Chris Lattner
a81556fb52 teach SimplifyDemandedBits that exact shifts demand the bits they
are shifting out since they do require them to be zeros.  Similarly
for NUW/NSW bits of shl


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125263 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:09:34 +00:00
Chris Lattner
81a0dc9115 Teach instsimplify some tricks about exact/nuw/nsw shifts.
improve interfaces to instsimplify to take this info.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125196 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 17:15:04 +00:00
Chris Lattner
aeaf3d484b Rework InstrTypes.h so to reduce the repetition around the NSW/NUW/Exact
versions of creation functions.  Eventually, the "insertion point" versions
of these should just be removed, we do have IRBuilder afterall.

Do a massive rewrite of much of pattern match.  It is now shorter and less
redundant and has several other widgets I will be using in other patches.
Among other changes, m_Div is renamed to m_IDiv (since it only matches 
integer divides) and m_Shift is gone (it used to match all binops!!) and
we now have m_LogicalShift for the one client to use.

Enhance IRBuilder to have "isExact" arguments to things like CreateUDiv
and reduce redundancy within IRbuilder by having these methods chain to
each other more instead of duplicating code.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125194 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 17:00:45 +00:00
Chris Lattner
35bda8914c enhance vmcore to know that udiv's can be exact, and add a trivial
instcombine xform to exercise this.

Nothing forms exact udivs yet though.  This is progress on PR8862



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124992 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-06 21:44:57 +00:00
Dan Gohman
5195b71941 Conservatively, clear optional flags, such as nsw, when performing
reassociation. No testcase, because I wasn't able to create a testcase
which actually demonstrates a problem.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124713 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-02 02:05:46 +00:00
Anders Carlsson
77bc49e5e2 Recognize and simplify
(A+B) == A  ->  B == 0
A == (A+B)  ->  B == 0



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124567 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-30 22:01:13 +00:00
Frits van Bommel
31726c154d Call SimplifyFDivInst() in InstCombiner::visitFDiv().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124535 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29 17:50:27 +00:00
Frits van Bommel
1fca2c32cc Move InstCombine's knowledge of fdiv to SimplifyInstruction().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124534 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29 15:26:31 +00:00
Duncan Sands
593faa53fa My auto-simplifier noticed that ((X/Y)*Y)/Y occurs several times in SPEC
benchmarks, and that it can be simplified to X/Y.  (In general you can only
simplify (Z*Y)/Y to Z if the multiplication did not overflow; if Z has the
form "X/Y" then this is the case).  This patch implements that transform and
moves some Div logic out of instcombine and into InstructionSimplify.
Unfortunately instcombine gets in the way somewhat, since it likes to change
(X/Y)*Y into X-(X rem Y), so I had to teach instcombine about this too.
Finally, thanks to the NSW/NUW flags, sometimes we know directly that "Z*Y"
does not overflow, because the flag says so, so I added that logic too.  This
eliminates a bunch of divisions and subtractions in 447.dealII, and has good
effects on some other benchmarks too.  It seems to have quite an effect on
tramp3d-v4 but it's hard to say if it's good or bad because inlining decisions
changed, resulting in massive changes all over.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124487 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28 16:51:11 +00:00
Nick Lewycky
df3bfae151 Fold select + select where both selects are on the same condition.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124469 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28 03:28:10 +00:00